Electrochemical-catalytic NH3 synthesis from H2O and N2 using an electrochemical cell with a Ru catalyst, Pd–Ag membrane cathode, and NaOH–KOH molten salt electrolyte at 250 °C†
Abstract
Using sustainable energy-based electricity to synthesize NH3 from H2O and N2 to release O2 not only contributes to making chemical fertilizer production carbon neutral, but also holds promise for the use of NH3 as a fuel. NH3 synthesis from water and nitrogen was conducted at around 250 °C and below 1.0 MPa by combining a molten salt electrolyte of NaOH–KOH, a Pd alloy hydrogen-permeable membrane cathode, a Ni anode, and a Ru-based catalyst on the cathode backside. The rate and current efficiency for NH3 formation were obtained as 11 nmol s−1 cm−2 (38 μmol h−1 cm−2) and 25%, respectively, at 30 mA cm−2, 1.0 MPa, and 250 °C. It was confirmed that the remaining percentage from the 100% current efficiency for NH3 production was attributed to the current efficiency for H2 production. The cell voltage was as low as 1.47 V at 30 mA cm−2 and increased to 1.95 V at 100 mA cm−2. The potential of this electrochemical system is discussed.
- This article is part of the themed collections: Research advancing UN SDG 13: Climate Action, Research advancing UN SDG 12: Responsible consumption and production and Research advancing UN SDG 7: Affordable and clean energy